Overview
ISO 5007:2003 defines a laboratory method for measuring and evaluating vertical whole‑body vibration transmitted through operator seats on agricultural wheeled tractors. Intended for conventional tractors with rubber tyres, unsprung rear axles and no low‑frequency cab isolation, the standard assesses seat suspension effectiveness over the frequency range 1 Hz to 20 Hz and specifies acceptance criteria and input spectral classes for three tractor mass groups (class 1: ≤ 3 600 kg; class 2: 3 600–6 500 kg; class 3: > 6 500 kg).
Key topics and technical requirements
- Scope and limits
- Tests vertical vibration transmitted via the seat only; not applicable to vibration through foot platforms, pedals or steering wheel.
- Laboratory simulation
- Uses a platform-mounted vibrator to simulate tractor inputs; vibrator must produce required vertical motion (example: sinusoidal ±7.5 cm peak‑to‑peak at 2 Hz).
- Input spectral classes are based on field measurements (ISO 5008 OECD track and field data) and grouped by similar ride characteristics.
- Measurement and analysis
- Frequency range: 1–20 Hz for seat transmissibility evaluation.
- Instrumentation and analysis meet ISO 8041 (type 1 instruments) and ISO 10326‑1 laboratory method; frequency weighting per ISO 2631‑1.
- Key metrics: SEAT (seat effective amplitude transmissibility) factor and maximum transmissibility ratio from damping tests.
- Test procedure
- Seats must be representative of production models and run in before testing (manufacturer’s procedure or minimum 5 000 cycles with monitoring at intervals).
- Run‑in uses an inert mass of 75 kg (±1 %) with adjustment to manufacturer’s settings or centre of stroke; transmissibility must stabilize within ±5% across successive checks.
- Seat adjustment, backrest angle and test posture are specified to ensure repeatability.
- Safety and reporting
- Safety precautions per ISO 13090‑1.
- Test report and seat identification requirements are specified.
Applications and users
ISO 5007 is used by:
- Tractor manufacturers and seat suppliers to validate and compare seat suspension designs.
- Test laboratories performing laboratory seat vibration testing and certification.
- R&D teams optimizing operator comfort and reducing whole‑body vibration exposure.
- Regulatory or procurement bodies seeking objective acceptance criteria for operator seats.
Practical benefits include objective evaluation of seat vibration attenuation, guidance for selecting seats to match tractor dynamic classes, and standardized repeatable test methods.
Related standards
- ISO 10326‑1 - Laboratory method for vehicle seat vibration (basic requirements)
- ISO 2631‑1 - Evaluation of human exposure to whole‑body vibration
- ISO 8041 - Vibration measuring instrumentation
- ISO 13090‑1 - Safety guidance for tests with people
Keywords: ISO 5007, operator's seat vibration, agricultural tractor seat testing, SEAT factor, whole‑body vibration, laboratory measurement, tractor input spectral classes.
